In many areas of commerce, containers and, in particular, stackable containers are used to hold and/or transport products. For the area of produce (e.g., fresh fruits and vegetables), such stackable containers are particularly important. In various conventional approaches (see, e.g., U.S. Pat. No. 5,860,590 and U.S. patent application Ser. No. 11/246,872, filed on Oct. 7, 2005), a stackable container is formed from a container blank. The weight-bearing walls of a container may conventionally include two wall flaps, one folded over the other. For example, referring now to FIGS. 1 and 2, a container blank 100 and an erected stackable container 110 are shown. Load bearing wall 111 of container 110 may be formed by folding wall flap 101 of blank 100 over wall flap 102 at bridge regions 103, thus forming projections 113. Thus, projections 113 are covered by the outer surface of the container blank. Furthermore, the rectangular base 106 and/or the side wall 102 may have holes cut in them to receive the upwardly directed projections 115 from a lower container in the stack. Thus, the holes and projections allow a stack of containers to be indexed such that they stack vertically.
Conventional packaging containers are typically formed from blanks made of corrugated board. Such corrugated board generally contains two outer layers of paperboard or cardboard (which generally has a relatively heavy weight), with an inner layer of corrugation (e.g., corrugated paper), but it may contain further layers (e.g., of an external paper or plastic sheet for further support, waterproofing and/or marking, e.g., with advertising and/or identification information; a further inner layer or sheet [e.g., of paper or plastic] between two layers of corrugation; etc.) or contain different materials (e.g., plastic sheet having a relatively high stiffness or modulus of elasticity). Conventionally, packaging containers are formed such that the “flutes,” or channels formed by the corrugation, are directed upward in the load bearing walls. Thus, referring again to FIG. 2, when indexing projections 113 are formed by folding flap 101 over flap 102 at bridge region 103, the areas 112 between the projections comprise uncovered flutes. As a result, moisture may collect in these flutes due to outdoor precipitation, condensation in cold storage, and/or other natural and/or unnatural events. This moisture in the flutes may weaken the container over time.
Therefore it is desirable to provide a container with good stackability (including indexing and relatively high load strength) while reducing degradation due to moisture collection.